JPH05230536A - Flame hardening method and device for casting gear - Google Patents

Abstract

PURPOSE:To automatically harden a casting gear by flame hardening without generating quenching cracks. CONSTITUTION:The tooth part T for one tooth-component of the casting gear W is heated by a flame heater and right thereafter, this gear W is rotated by one tooth-component within the perpendicular plane and cooling water is injected by a cooling water injector 9 to the tooth part Tn heated right under the nozzle 8 of the flame heater by which the tooth part is rapidly cooled. This operation is repeated by as much as the number of the teeth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when flame-quenching a cast gear, automatically does this without human intervention to improve the quenching efficiency and at the same time stabilize and improve the quenching quality. The present invention relates to a flame hardening method for a cast gear and a device therefor.

[0002]

2. Description of the Related Art A cast gear has an original shape formed by casting, its teeth are machined by a gear cutting machine, and then the teeth are hardened by hardening to increase the working strength. Most of the conventional quenching of the teeth of the cast gear is induction hardening. That is, set the gear in a predetermined position using a chuck device, etc., and at the same time induction heat all the tooth parts by high frequency, then remove the heated gear from the chuck device and move it to the oil tank to move the entire gear. It is a method of quenching by cooling with oil while rotating. This method has the advantage of uniformly quenching all teeth, but it takes time from the end of heating to the oil cooling, during which the heating part (tooth) of the gear cools. Will end up. For this reason, in order to prevent the necessary heating part of the gear from cooling after the heating is finished and before the oil cooling, the heating temperature is set higher than the temperature originally required for quenching, and Heats up to the root portion of the tooth that is not necessary, and if the entire gear is oil-cooled in this state, quench cracks easily occur at the tooth tip or the tooth root.

Flame quenching is known as a quenching method for induction hardening, and it is possible to quench a cast gear by this method. However, this flame quenching is highly dependent on the skill of the operator, so its advantage is exhibited for complicated shapes, but generally for mass-produced products such as gears. It was inadequate due to inefficiency. Also in this flame quenching, if it takes time from the heating to the cooling, the same problems as in the above-described induction quenching occur.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention utilizes flame quenching, which has been unsuitable for cast gears, to make the cast gears automatic and to prevent The main problem is to quench only the necessary parts in a concentrated manner so that quench cracking does not occur and the quenching is performed with a constant quality and high efficiency.

[0005]

In order to solve this problem, the basic means adopted by the present invention is that, when flame hardening of a casting gear is performed, immediately after heating the tooth portion of one tooth of the casting gear by flame. First, the operation of rotating the gear by one tooth in the vertical plane and injecting cooling water to the tooth portion heated immediately below the nozzle portion of the flame to rapidly cool the tooth portion is repeated by the number of teeth. Further, in order to keep the quenching temperature of each tooth constant, the heating time for each tooth is gradually shortened from the start of quenching.

[0006]

Since the heated tooth portion is rapidly cooled by jetting the cooling water immediately after the tooth portion of one tooth of the gear is heated by the flame, the time required from the end of heating to the water cooling. Becomes extremely short. For this reason, like the conventional quenching method, the heating portion (tooth portion) of the gear is not cooled from being heated to water cooling or oil cooling, so that only the necessary portion of the tooth portion is intensively heated. Sufficient and no distortion of the heating part (tooth part) even after water cooling. Therefore, it is possible to quench the gear with high accuracy without causing quenching cracks. In addition, the gear rotation device rotates the gear one tooth at a time, and each tooth of the gear is automatically hardened one tooth at a time, so the quenching efficiency is increased, and at the same time the quenching quality is improved and stabilized. Be done.

[0007]

EXAMPLES The present invention will be described in more detail below with reference to examples. FIG. 1 is a plan view in which a part of the flame hardening apparatus according to the present invention is cut away, FIG. 2 is an enlarged front view of the same, and FIG. 3 is a view after rotating the gear W by one tooth. FIG. A flame quenching apparatus according to the present invention includes a gear rotating device A for chucking a cast gear W to intermittently rotate the gear W in a vertical plane by one tooth.
A nozzle is arranged on the side of the gear W chucked by the gear rotating device A, and a flame heating device B for intensively applying a flame to one tooth of the gear W to heat the gear W, and the flame heating device B. An injection nozzle is arranged immediately below the nozzle of the device B, and is composed of a cooling water injection device C for intensively injecting cooling water to the teeth of the heated gear.

The gear rotation device A is a motor 1 with a brake.
Is transmitted to the decelerator 3 via the clutch 2, a chuck 5 is attached to the output shaft 4 of the decelerator 3, the motor 1, the clutch 2 and the decelerator 3 are integrated, and Attached to a support plate 6 supported by the speed reducer 3
The output shaft 4 of is projected from the support plate 6. The illustrated gear W is a spur gear having a cylindrical boss 7, and the portion of the boss 7 is chucked by the chuck 5. The rotation of the motor 1 is decelerated by the decelerator 3 and output to the output shaft 4, the output shaft 4 intermittently rotates by one tooth of the gear W, and the rotation stop time of the output shaft 4 (in other words, The motor 1 is controlled such that the flame heating time by the flame heating device B) becomes a preset time. In order to keep the heating temperature of each tooth portion for quenching substantially constant, the heating time for each tooth portion by the flame heating device B (rotation stop time of the output shaft 4) is 5 from the tooth portion at the start of quenching.
The length is gradually shortened up to the third tooth, and thereafter it is almost constant.

The tip 8a of the nozzle 8 of the flame heating device B
Is arranged horizontally to the side of the tooth portion T of the gear W chucked by the chuck 5 and on the same vertical plane as the gear W chucked with the boss 7 horizontal. There is. This flame heating device B burns acetylene, propane, city gas, etc. together with excess air or oxygen, and blows out the flame generated thereby from the tip portion 8a of the nozzle 8 so that the gear W to be hardened is This is a device for intensively applying heat to one specific tooth T.

The cooling water injection device C is the flame heating device B.
Is a water cooling device for intensively injecting the temperature-controlled cooling water to one tooth portion T of the gear W heated by flame to cool the tooth portion. The tip 9a of the nozzle 9 of the cooling water jetting device C is the nozzle 8 of the flame heating device B.
Is disposed immediately below the tip portion 8a of the. This nozzle 9
Is for spraying cooling water to the heated tooth portion T of the gear W to cool the tooth portion T, so that the tip end portion 9a thereof is on the tooth surface of the vertically supported gear W as shown in FIG. The nozzles are arranged so as to be inclined with respect to each other, so that the jet of cooling water that hits the tooth flanks can smoothly flow after colliding with the tooth flanks. Cooling water is intermittently jetted from the cooling water jetting device C.

A lock device D is provided on the side of the gear W vertically chucked by the chuck 5 opposite to the side on which the flame heating device B and the cooling water injection device C are arranged. When the flame heating device B flame heats the tooth portion T of one tooth of the gear W, the locking device D determines and locks the position of the tooth portion T of the gear W,
This is a device for constantly maintaining the heating position of the tooth portion T of the gear W to prevent the heating variation. In the embodiment, the engagement pin 12 is engaged with the main body 11 by the action of a solenoid (not shown) built in the main body 11.
When the gear moves in and out, and when the gear protrudes, the engaging pin 12 enters and engages between the adjacent tooth portions T of the gear W, thereby locking the gear W.

Then, in order to quench the tooth portion T of the gear W using the flame quenching apparatus described above, the boss 7 of the gear W is chucked by the chuck 5 and the gear W is vertically arranged. At the same time, when the engaging pin 12 of the lock device D is projected and inserted between the adjacent tooth portions T to be engaged with each other, the tooth portion T of the gear W is always locked at a fixed position. .. As shown in FIG. 2, the flame is constantly emitted from the nozzle 8 of the flame heating device B and the flame is applied to the (n) th tooth Tn calculated from the reference tooth and heated for the set time. It When the set time has elapsed, as shown in FIG. 3, the lock device D and the cooling water injection device C operate, the engagement pin 12 of the lock device D retracts, and the lock of the gear W is released. , The cooling water is jetted from the nozzle 9 of the cooling water jetting device C, and the motor 1 is operated after the lock device D is operated.
Starts and rotates the gear W by one tooth. By the rotation of one tooth of the gear W, the cooling water is jetted for a predetermined time to the tooth portion Tn of the gear W heated by the flame to be rapidly cooled. Therefore, the tooth portion Tn of the gear W is rapidly cooled by the jet of cooling water immediately after heating. After rotating one tooth of the gear W, the tooth portion Tn immediately after being heated is rapidly cooled as described above, and at the same time, the locking device D is actuated again to lock the gear W by the engagement pin 12. hand,
During cooling of the heated tooth portion Tn, the heating of the (n + 1) th tooth T (n + 1) from the reference tooth is started.
The injection of the cooling water to the heated tooth portion Tn is stopped after the set time has elapsed. After that, the same operation is repeated for the number of teeth, and the hardening of all the tooth portions T of the gear W is completed.

Here, as described above, the heating time for each tooth portion by the flame heating device B (rotation stop time of the output shaft 4) is from the tooth portion at the start of quenching to the fifth tooth portion. The heating temperature of each tooth is kept substantially constant, and the quenching state is made uniform. Further, the temperature of the cooling water to be sprayed on the heated tooth portion is controlled, and the difference from the heating temperature of the tooth portion is kept substantially constant. In a concrete example, immediately after heating the tooth portion of the gear up to about 850 ° C, 25 to 30
The cooling water of ° C was sprayed onto the heated tooth portion, and the difference between the heating temperature and the cooling water was about 830 ° C.

In this way, the tooth portion T of one tooth of the gear W is formed.
Immediately after being heated by the flame heating device B for a set time, the gear W is rotated by one tooth, and the cooling water is jetted to the tooth portion T immediately after heating for a set time to rapidly cool. , All the tooth portions T of the gear W are automatically flame-hardened. The heating time of the tooth part due to the flame, the heating part, or the time of the cooling water injection to the heated tooth part, the injection part,
Since both are constant, quenching quality is stabilized.
Further, it is possible to appropriately change the quenching conditions as described above according to the material of the gear and the like to perform flame quenching with a constant quality.

As described above, according to the flame quenching method of the present invention, as shown by hatching in FIG. 4, it is necessary to form the tooth portion without heating the root portion of the tooth portion that does not need to be quenched. Immediately after only the part is effectively heated at the required temperature, cooling water is sprayed to the heating part to cool it, so that the part of the pitch circle that is most necessary as a gear can be effectively quenched, and at the same time, the tooth tip part Or, there will be no occurrence of quench cracks at the tooth roots.

In the above embodiment, quenching of spur gears has been described, but when quenching worm gears, helical gears, etc., the nozzles 8 of the flame heating device B and the cooling water injection device C, It suffices to make the shape of the tip of 9 correspond to the shape of each tooth so that only one tooth is intensively heated or cooled.

[0017]

EFFECT OF THE INVENTION The flame quenching method for a casting gear according to the present invention is to rotate the gear by one tooth in the vertical plane immediately after heating the tooth portion of one tooth of the casting gear by a flame,
Since the operation of injecting the cooling water into the heated tooth portion immediately below the nozzle portion of the flame and rapidly cooling the tooth portion is repeated by the number of teeth, the following effects are achieved. (1)
It is possible to automate flame quenching for cast gears, which has been considered difficult in the past. (2) Since it is possible to automate the flame quenching for the cast gear, the quenching efficiency by flame quenching can be improved all at once, and at the same time, the difference in the skill of each worker is eliminated, and the quenching quality is stabilized and improved. And is planned.
(3) Immediately after heating the tooth portion of one tooth of the gear, the cooling water is jetted to the tooth portion for rapid cooling, so the time from the end of heating to the water cooling is extremely short, and the heating is finished. The heated tooth portion is hardly cooled during the period from the start to the cooling. As a result, it suffices to intensively heat only the necessary parts of the gear teeth, and even after water cooling, the heating part (teeth)
It is possible to carry out flame quenching of gears with high accuracy without distortion occurring in the gears and without causing quenching cracks. (4) Depending on the material of the cast gear, etc., by appropriately changing the quenching conditions such as the heating time of the tooth part by the flame, the heating part, the time of cooling water injection to the heated tooth part, the injection part, etc. It is possible to perform optimum quenching.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of a flame hardening apparatus according to the present invention.

FIG. 2 is an enlarged front view of the same.

FIG. 3 is an enlarged front view similarly after the gear W is rotated by one tooth.

FIG. 4 is a diagram showing a heated portion of a tooth portion according to the quenching method of the present invention.

[Explanation of symbols]

 A: Gear rotation device B: Flame heating device C: Cooling water injection device D: Lock device T: Gear teeth (tooth) W: Gear 8: Flame heating device nozzle 9: Cooling water injection device nozzle

Claims (4)

[Claims] 1. Immediately after heating a tooth portion of one tooth of a cast gear by a flame, the tooth portion is rotated by one tooth in a vertical plane to heat the tooth portion just below the nozzle portion of the flame. A flame quenching method for a casting gear, characterized in that the operation of injecting cooling water into and cooling rapidly is repeated for the number of teeth. 2. The flame quenching method for a casting gear according to claim 1, wherein the heating time for each tooth is gradually shortened from the start of quenching to keep the heating temperature for each tooth constant. 3. A gear rotating device for chucking a cast gear to rotate the gear intermittently one tooth at a time in a vertical plane, and a nozzle provided at a side of the gear chucked by the gear rotating device. Immediately after heating the tooth portion of one tooth of the gear by the flame heating device and a cooling water injection device in which an injection nozzle is arranged immediately below the nozzle of the flame heating device. The casting is characterized in that the gear is rotated by one gear by the gear rotation device, and the cooling water is sprayed to the tooth portion heated by the cooling water spraying device to rapidly cool the casting. Gear flame quenching device. 4. A locking device for determining and locking the position of the tooth portion of the gear when heating the tooth portion of one tooth of the gear by the flame heating device. Flame hardening device for a cast gear according to.